Fight Invasive Species With More Invasive Species!

I watched a National Geographic program about cane toads, an invasive species in Australia. In the 1930s, some growers brought Central American cane toads in to eat beetles that threatened the sugar cane crop. The beetle problem was solved as expected, but the cane toads have proliferated and occupy a big part of Northern Australia. They are venomous and kill anything that tries to eat them, their eggs or their tadpoles. Central American predators evolved immunity, but the Australian critters don’t have it. Even crocodiles disappear when the cane toads move in. They abound and overrun residential areas and are nuisance. Their venom can’t penetrate the skin, but it will kill you if you swallow it or it will blind you if it gets in your eye. Your family pets will die if they bite a toad.

A group of volunteers in Darwin has drawn a line of demarcation beyond which they allow no toad to pass. It’s a tough business killing off toads one by one. A scientist proposes to introduce a toad virus that will arrest their development, but there is some concern about compounding the problem by adding another invasive species. I reckon that importing a few thousand Central American gators with immunity to the venom would be helpful. What’s the downside? They already have crocs, so gators wouldn’t pose a hardship. They’re maybe less deadly even.

In Texas, a scientist imported a species of insect that lays its eggs in fire ants as a means of controlling the spread of the ants. The bug’s life cycle is tied up with the fire ant in that their larvae consume the fire ant hosts and come out of the severed head when they are ready to mate. They mate and commence to poking fire ants during their brief adulthood so there is no big impact on the environment or local ecosystem. Or so they hope.

Water hyacinth was choking up Lake Victoria until a water hyacinth eating bug was introduced into the lake. The hyacinth is under control, snail populations are down, and snail borne disease has been reduced. So far no negative impacts from hyacinth eating bugs have been identified.

I grew up with kudzu, an invasive species that had been introduced to fight erosion. It fights erosion all right, but it grows rapidly and takes over if you don’t fight it constantly. It envelops trees and kills them. It envelops buildings and covers paths and fences. I don’t know why we don’t bring in a kudzu eating critter or two from Asia. If that critter gets out of control, we can import a predator. Tigers would be cool. I’ve never heard of tigers getting out of control. Of course, you’ll get the usual selfish whining from parents about how their kids might be at risk from tiger attacks. I have two words for them. Parental. Responsibility.